I've been reading about all kind of symptoms and problems for over a month now without any results, so I've finally decided to make a post about it.

1990 7.3 IDI F250 single cab, 3.73 limited slip differential. Driven 347 000 kilometres (215000 ish miles). Owned by the local society's most renowned Ford mechanic (which unfortunately passed last year) which serviced it often.

So the issue is like this: idle was low when I got it, but I immediately adjusted it up to 750 RPM. 5 months ago it started spewing white smoke and a low end ticking noise. Replaced all injectors with new ones (pressure tested as well). Solved smoke and ticking. Done usual service and replaced most of the relays and small electronic components.

Though a month ago, a different kind of ticking recurred, thought it was a bad lifter, inspected lifters, did a compressiontest, all was as good as new. Replaced all filters and fluids. Still the same. Now the car wobbles while idling, as if it was missing a little bit, because it wobbles every half second or so. We suspected the IP was going bad, but flowtest reveils it's okay. Then a week after, the idle drops, even while being adjusted as high as possible, and when braking in drive (while still) the idle drops down to 500 RPM. Mileage has also dropped from 17 to about 11, and the engine significantly lacks power as well.

The tick almost seems like from a cracked flexplate or bad TC, but we ruled it out last inspection. Though these symptoms have turned much worse the last week.

Any ideas? A remanufactured IP costs 2/3 of a whole months salary here in Norway due to taxes and customs, so I want to be sure before crippling my economy for half a year.

 

any possibility of fuel contamination? may need a compression test again, have you a laser temperature gauge, you can check each cylinder temperature with?

 

Advance the timing a bit and see if it helps. You can always undo it; it might just fix it.

 

Even if taxes and customs was 30%, an R&D pump would still be under $900.

RD2-80 Injection Pump

Of course that isn't cheap, but he stands behind his work and its worth the price.



Regardless, you are right to exhaust all options before investing in a new IP. But you really have tried a lot of the things that I would have tested. Have you checked your motor mounts? maybe you got a ripped mount that is causing the wobble and the ticking (some metal line somewhere it hitting).

The idle dropping makes me worry about the IP. When my IP went, it had been acting funny for weeks. Then I got stranded twice in a few weeks. Got an R&D pump and never had a problem again.

 

That's a good point. Bad timing can really mess with your MPG.

 

Could also be exhaust valve guides. When you checked the lifters, was there any area under the valve covers with gooey oil residue?

 

All the comments are much obliged!

I just ordered a new IP as I know this one for sure is the original with 217 000 miles on it's conscience, so it won't hurt to change it anyways. We have quite a lot of taxes and different fees, but I'll survive (maybe).

We saw nothing unusual when we removed the valve cover. Everything looked as good as new. Though the exhaust sounds like a darned locomotive, so we now suspect that it's either the IP that's so worn that it struggles to properly inject fuel, causing half-misses and therefore making the puffing sounds and what sounds like injector-knock ticking.

Either that, or I'm better off doing a complete head rebuild.

Or possibly cracks in the flexplate/bad TC.

 

Don't worry about that if you don't have to; I had an exhaust valve guide go spectacularly wrong once due to the valve beating it's way into the piston due to not being rebuilt correctly.
The valve guide had almost 1/8" of play, and the valve was just kind of floating around in there. At idle, you'd never notice it. It was only under load, where the engine quieted down enough to make a slight 'ticking' sound. And no smoke, either.


These engines are amazingly tough, and you can get away with a /lot/. 99% of the issues you'll find stem from fuel problems - it's either fuel not getting TO the IP correctly, the IP is shot, or the injectors are shot. And the good news is that replacing an IP or injectors is easy on an IDI(maby 4 hours work with a few tools, max).
It's not like a Duramax, where you have to pull half the engine apart just to replace an injector... <_<

 

I've finally replaced the IP with a new one. The difference in power, torque and pick-up is amazing. Though the rest of the symptoms consists. Looks like only a head rebuild will get me out of these troubles. Though I face another challenge: timing the IP. I've timed it by ear, but that won't do it. I was reassured by Ford that they could time it, but when I finally paid them a visit they were shocked and told me that "we don't do AMERICAN Fords!!!". Horrible.

None of the dealers or mechanics here are able to time it, and I don't have the possibility to buy a set of tools and instruments that I'll only use once ​.

 

Here's a video I made about timing an IDI van. It'll be easier to do this on your truck. It has all the tools you would need to turn the IP. Just buy a few of those wrenches and a turn buckle, then bend one of the wrenches as shown in the video. Even if you don't have the timing gun, you could try a half dozen variations of the IP, drive it in between, and then calculate your MPG each time. Then pick the best one to set it at. You won't know exactly what your timing is, but at least you will have the most efficient timing.

 

Very much obliged! Yet I'd like to ask how much it costs for timing gun? I've phoned and searched around in Norway, but nobody sells them.

 

I recently bought my own timing gun and ferret adapter, and started a thread when i was shopping around:

https://www.ford-trucks.com/forums/1...d-adapter.html

The gun can be pretty much any decent timing gun, but the expensive part (and slow to obtain) is the Ferret Adapter. It converts the conductance or capacitance of the 1st injector to a signal that the gun can use. They are sold separately from the timing gun. As far as I could tell, this was the only place that sold one for the IDI engine:

Ferret Instruments V765-01 Injector Tester - Fuel System Tools

 

Oh my. Thank you very much for the information! I think I'll break the piggy bank then... 😂